Question

The mean of five numbers is 4. If 1 is added to each other, then the new mean is

(a) 4 (b) 5 (c) 3 (d) 5.5

Answer 1

Mean of five numbers = 4
Sum of five numbers = 5 $\text{×}$ 4 = 20
$$\begin{gathered} \mathrm{New}\mathrm{mean}=\frac{\mathrm{Sum}\mathrm{of}\mathrm{observations}}{\mathrm{Number}\mathrm{of}\mathrm{observations}} \\ =\frac{20+1+1+1+1+1}{5} \\ =\frac{25}{5} \\ =5 \end{gathered}$$
Thus, the new mean is 5.
Hence, the correct option is (b).